Photopolymerization synthesis of hydrogels. Release studies of non-steroidal anti-inflammatory drugs.

A. GALLASTEGUI; M. B. SPESIA; R. J. J. WILLIAMS; C. M. PREVITALI; M. L. GOMEZ (*)

Maresias, Sao Paulo

Encuentro; XII Latin-American Meeting on Photochemistry and Photobiology; 2015

USP - Sao Paulo and UNICAMP ? Campinas

Synthesis and characterization of hydrogels employing a modified silsesquioxane with amino and methacrylate groups as co-initiator and crosslinking agent was carried out. The presence of these functional groups in the modified silsesquioxane provides a double role: the amino groups act as co-initiators, while the presence of several acrylate groups makes this compound a good crosslinking agent [1]. The synthetic dye safranine was used as sensitizer of the polymerization reaction in order to employed visible light [2]. Hydrogels were synthesized with a 10:90 weight ratio of acrylamide: 2-hydroxyethyl methacrylate. The synthesis was carried out using different proportions of the modified silsesquioxane, allowing modulating the properties of the materials as systems suitable for controlled drug release. Hydrogels prepared in this way were characterized using several techniques such as: SEM, FTIR and DSC. Their ability to swell as function of pH and temperature was also investigated. The results show that the percentage of modified silsesquioxane employed affects the swelling capacity of the hydrogels. Thus it is possible modulates the properties of the materials from variation of crosslinking agent in the formulations. Additionally, incorporation assays of non-steroidal anti-inflammatory drugs aspirin and ibuprofen during the photopolymerization process were carried out. Reagents were successfully incorporated without changing the properties of synthesized hydrogels. Furthermore, the active drugs were not altered by the photopolymerization reaction. This technique facilitates the incorporation of higher amounts of drugs compared to other conventional methods of incorporation such as posterior absorption [3]. Release studies were followed by spectroscopic techniques. The experimental results were fitting by the empirical equation proposed by Peppas and col. [4]. It was found that the release of these drugs depends on the composition of the hydrogels and the pH of the medium in which the liberation takes place. In most cases a progressive release of over 80% was achieved. Cytotoxicity studies showed that these materials do not exhibit hemolytic activity, which would make them suitable as new biocompatible systems for controlled drug release.